Do note the definitions for deploys. A deploy preview as triggered by a PR/merge, takes the form deploy-preview-42--yoursitename.netlify.app as opposed to a production deploy preview which takes the form 61bca6635ddd093d3d0993e2--vigorous-lewin-937bb3.netlify.app (deploy previews have a permalink like this too.)
If it is a deploy preview, you’ll find this thread useful
So this is working as expected. If you don’t want Netlify to build for your commits, you can set [skip netlify] anywhere in your commit message and Netlify will not build for it.